1. Field of the Invention
This invention relates to an improvement in space vehicles and more particularly, but not by way of limitation, to an improved liquid propellant rocket booster for launching a space vehicle, which booster includes an arrangement for precluding crash damage and sea water damage to the rocket booster engine when the booster returns to a salt water body for recovery.
2. Description of the Prior Art
It is well known in the art, to associate a number of solid and liquid rocket boosters and a space vehicle in order to launch a space vehicle or a payload into a desired orbit around the earth or other desired extraterrestrial path. It is common to use solid rocket boosters and liquid propellant rocket boosters to propel the associated space vehicle to at least a desired first stage of travel. At present, after a launch an attempt is made only to recover, refurbish and reuse solid rocket boosters. The reason for this is that rocket boosters commonly descend into salt water bodies for recovery. Salt water damage to a solid rocket booster is considered to be of minor consequence since the relatively simple rocket motors of such boosters are completely rebuilt prior to reuse. However, in the instance of liquid propellant rocket boosters the crash damage to the rocket engine upon descent of the booster into a salt water body and the subsequent entry of salt water into the thrust chambers and interior of the complex liquid propellant turbopumps render a liquid propellant rocket booster incapable of reuse without having first undergone expensive major overhaul.
Accordingly, it is of paramount importance if an attempt is to be made to reuse a liquid propellant rocket booster to protect the rocket engine from potential impact damage as the liquid rocket booster descends into a salt water body, such as an ocean, and to preclude resulting environmental damage to the engine prior to recovery of the rocket booster from the sea water. Failure to provide adequate protection form these dangers would render a liquid propellant rocket booster uneconomical to use in comparison to a solid rocket booster.
Past attempts at protecting a liquid propellant rocket from such damage have proved to be unsatisfactory. Such efforts have included large mechanically operated closures for the thrust end of the rocket engine. Such a closure was moved from a stowed position outboard of the booster to a deployed position so that the open end of the rocket engine would be sealed in the manner of sealing a jar with a lid.
These devices unfortunately are very heavy, involve complex mechanisms, and cause severe interface problems with the conventional means for securing a rocket booster and associated space vehicle to a launch pad. The problem of adequately protecting a liquid propellant rocket booster for recovery from a salt water body in a practical manner has not been provided by the prior art.
The present invention does provide a simple, low cost, lightweight practical solution to the problem of providing adequate protection for a liquid propellant rocket booster to enable reuse thereof after recovery from a salt water body. It has current importance in the art since it is contemplated that the rocket boosters for a space vehicle such as the NASA advanced space shuttle of the United States will utilize liquid rocket boosters in place of solid rocket boosters.
The following patents, while of interest in the general field to which the invention pertains, do not disclose the particular aspects of the present invention that are of significant interest.
U.S. Pat. No. 4,504,031 issued on Mar. 12, 1985 to Dana G. Andrews discloses an inflatable braking member that is deployed around a space vehicle by introducing gas into it. The reduction of velocity of the space vehicle is controlled by directly varying the drag of the vehicle to compensate for variations in the density of the atmosphere by varying the thrust of the main rocket motor of the space vehicle and/or varying the shape of the braking member as the space vehicle descends, main rocket nozzle end first. The braking member is jettisoned after the space vehicle leaves the atmosphere to enter a low earth orbit.
U.S. Pat. No. 4,426,038 issued on Jan. 17, 1984 to Frank S. Inman et al discloses a non-radiating cloth exit cone for a flared woven refractory cloth structure having the shape of the frustrum of a cone with refractory felt sewn to the exterior surface of the cloth structure for thermal insulation of the cloth structure and a sacrificial ablative material incorporated in the interior surface of the cloth structure. The cloth structure is stowed in a collapsed or retracted configuration and is extended to an operating position after motor ignition to provide a large expansion ratio nozzle for a rocket motor.
U.S. Pat. No. 4,638,947 issued on Jan. 27, 1987 to Vance W. Jaqua et al also relates to a rocket engine nozzle extension. A pneumatic bag within the fixed nozzle of a rocket engine is inflated to push and unfold the nozzle extension. After the nozzle extension is completely formed, the pneumatic bag may be jettisoned by firing the rocket engine.
U.S. Pat. No. 3,711,027 issued on Jan. 16, 1973 to Lee F. Carey relates to an extendable nozzle for a rocket engine. The nozzle extension is deployable from a compactly stowed condition to an extended length condition and features the use of a frusto-cone shaped member formed of thin and lightweight convoluted sheet material, such as columbium or an aluminum foil honeycomb stock. A temporary jettisonable cover member is pressurized to unfurl the extendible nozzle and then is detached.
U.S. Pat. No. 3,482,783 issued Dec. 9, 1969 to F. R. Nebiker et al relates to an inflatable rocket nozzle which includes an inner fabric formed to the shape of a high area-ratio nozzle, an outer fabric spaced from but substantially conforming to the shape of the inner fabric and a plurality of drop yarns extending between and attached to each of the fabrics to hold the fabrics in a predetermined spaced apart relationship when they are moved apart. Pressure means expand the inflatable nozzle when the rocket has risen to an altitude in the earth's atmosphere.
None of the prior art uncovered discloses a method and an arrangement to protect a liquid propellant booster rocket from crash damage and environmental damage for recovery of the rocket booster from a sea water landing so as to permit reuse thereof without major overhaul.